NEW YORK (CNN/Money) -
The firm that already arranged for two millionaire space tourists to visit the International Space Station is getting ready to sell trips to the moon for $100 million each.

Space Adventures, an Arlington, Va., based company, announced plans Wednesday morning for two passengers to ride a Russian Soyuz rocket to the moon and back as soon as 2008. A Russian cosmonaut would pilot the space craft.

The Soyuz would travel around the far side of the moon and then return to Earth without orbiting or landing, according to Eric Anderson, CEO of the firm.

Anderson said the firm has identified more than 1,000 people with both the financial resources and the interest to consider making the trip for that sum, although he couldn't say how many he expects will eventually pay the $100 million price tag.

"There are almost 1,000 billionaires and you don't need to be a billionaire to do it," he said. "All it takes is two to do this. There are people out there with $100 million yachts and $100 million homes."

He said the cost of the first flight would cover the research and development expenses of the mission, and that future lunar flights could cost less, although he wouldn't give an estimate as to how much less, nor how big a deposit the ultra rich space tourists would have to pay to reserve one of the first two seats.

"There will only be one first private mission to the moon," said Anderson.

The challenge of finding two passengers to pay $100 million each is probably greater than making a trip to the moon for that relative bargain cost, said Charles Lurio, independent private space flight consultant.

"Going around the moon for a couple hundred million dollars is reasonable," said Lurio, who is not associated with Space Adventures or the Russian space program. "It's not a question of the technology. It's about how smart you are about using the capabilities."

But Lurio said it's very difficult to know if there are even the two passengers Space Adventures is looking for ready to pay a nine-figure fare.

"I don't know the answer and I don't think anybody else knows," he said. "The question is answerable only by putting it out there. Whether people will pony up the $100 million a pop is dubious, but it's certainly possible and I wish them luck with finding them."

Space tourism growing

The firm arranged for American Dennis Tito to ride a Soyuz to the International Space Station in 2001, followed by South African Mark Shuttleworth, who visited the following year. American Greg Olsen is set to make the third privately financed trip in October. Each paid $20 million.

Olsen appeared at the press conference announcing the lunar mission plans and said he would be one of those interested in a seat on the first flight. Olsen is the head of Sensors Unlimited, a New Jersey firm that makes highly sensitive near-infrared cameras, which he founded in 1992 and sold for $700 million in 2000.

"Who wouldn't want to go to the moon?" he said. "I must say I'm intrigued by the possibility. I have total confidence in the Soyuz vehicle. But one flight at a time."

In addition Space Adventures is taking deposits for people looking to spend just over $100,000 for a suborbital flight that will take passengers into the weightlessness of space for about 15 minutes at a time.

Virgin Atlantic founder Richard Branson also has formed a company called Virgin Galactic, which is also planning suborbital flights as early as 2008 for $200,000, using a spacecraft being designed by Burt Rutan, who won the $10 million X-prize by creating the first privately financed space craft late last year.

A view of the little seen far side

The proposed lunar mission would take the spacecraft within 100 kilometers, or about 62 miles, above the far side of the moon -- the side that is always turned away from Earth. Because it faces away from the Earth it has a surface more scarred by meteors than the side facing Earth.

The mission would be planned for when there is a new moon on Earth, so that the far side would be bathed in sunlight. That would give the mission the chance to take high-resolution photographs of the far side that weren't possible the last time a spacecraft orbited that side the satellite.

A mission that fully orbited the moon without landing would cost significantly more than this planned lunar flyby, said Chrisopher Faranetta, vice president of the orbital space flight program for Space Adventures, because much more fuel would need to be carried.

The Russian space program has previously sold seats on already-scheduled Soyuz flights going to the International Space Station, which allowed it to collect incremental money needed for the space program there.

Anderson said the lunar mission requires 10 times the total fares now being collected on the seats to the space station because this flight would be paid for completely by the passengers, and it would require two separate launches of both the Soyuz and the booster rocket with which it will dock in Earth's orbit.

Anderson said that the Soyuz is a very cost effective spacecraft; it uses what he described as "state of the art but off-the-shelf technology." While the $200 million is needed to cover both the mission and the necessary research and development, Faranetta said it should still be a money-maker for the Russian space program.

The Soyuz was originally designed during the 1960s U.S.-Soviet space race to be a lunar spacecraft, but it doesn't have the capacity to reach the moon in its current configuration. It would have to attach to a booster in low Earth orbit, either soon after reaching orbit or after a stay at the International Space Station, according to Anderson.

Anderson also said the Soyuz has proved its self as a very cost effective and dependable spacecraft, with more time carrying passengers in space than any other spacecraft design.

There has not been a manned mission to the moon since Apollo 17 in December of 1972. A total of 24 men have traveled to the moon, three of them making the trip twice. Half of those 24 men walked on the surface. But Anderson, who was born after the last manned lunar mission, said it's import to return for reasons of scientific exploration as well as the adventure of the trip.

"We're going to show that private companies can carry out exploration 250,000 miles from Earth," he said. And while he said he hoped to eventually have paid visits to the surface of the moon, he wouldn't estimate the timing or the cost of such a mission.